Ingredients to make 20 to 24 Thumbprint Cookies:
1 stick (1/2 cup) soft unsalted butter
1/3 cup powdered sugar (not sifted)
1 large egg yolk
1 teaspoon vanilla extract
1/8 teaspoon almond extract
1/4 teaspoon fine salt
1 1/4 cups all-purpose flour (5 ounces by weight)
1/2 cup fruit jam to fill centers